Characterisation of crystalline wax in asphalt binder by X-ray diffraction

To develop a rapid measurement method for the wax in asphalt, X-Ray Diffraction (XRD) tests were performed on asphalt binders. In addition, a simple temperature control system was developed. Different laboratory aging tests were carried out. What’s more, asphaltene structural parameters were calculated using the model developed by Yen et al. and pure wax doped asphalts were prepared. The results show that scan rate and temperature will affect the intensities of diffraction peaks. Oxidative aging has a complex effect on the crystalline wax in asphalt binders derived from different crude oils and several possible mechanisms are proposed. The positions of n-alkane characteristic peaks in the molten state are in good agreement with the positions of the wax peaks found in the asphalt binders. XRD is a promising method to measure wax in asphalt as it is fast, accurate and sensitive to high molecular weight pure wax.